Allow me to quote from the official grow guide.
The question is often asked, "can I have TOO MUCH light?". The basic answer is NO. (en-oh)
According to the law of diminishing returns, you could theoretically reach a point when your plants just couldn't absorb any more light but it would be IMPOSSIBLE to have that many lights in your space.
Heat from the lights would become a problem long before you ever reached that point. So use as many lights as you want, just control the heat.
BEAUTIFUL SETUP by the way
